May 20 2011:
So why gender pairs? Why not equal exchange of genetic material as a hermaphroditic species? Why not multiple genders? The answer is "intragenomic conflict." Please bear with me...

There are many layers of competition/cooperation- competing against another male to attract a female, competing against classmates, neighbors, races, and other groups of species. The caveat here is that we also must also cooperate to be successful... we make friends, collaborate on projects, we replant trees and try to keep our flora and fauna in balance because clearly these things are good for humanity.

The struggle for existence is a delicate balance between selfishness and cooperation.

Sexual reproduction in many species exhibit two genders because the fusing of two cells is accompanied by a battle of the organelles, specifically mitochondria. This battle threatens the survival of the offspring, and so one gamete began to concede to ensure the survival of the offspring- and it's genetic material. The genetic material of those gametes that conceded battle proliferated. This is the birth of two genders, those that concede this battle (male), and those that do not (female).

"Soon any deviation from a fifty-fifty ration of [those that concede] and [those that do not] would benefit the rarer type and cause the ratio to correct itself." --The Red Queen by Matt Ridley

The consequence of sex by fusing two cells is the creation of two genders. Some sex occurs by conjugation (slime molds, some mushrooms & protozoa), where a channel is formed in which the genetic material (and not organelles) is passed, resulting in no battle and no need for concession. Sure enough, we find multiple genders occurring in these species. A slime mold has up to 13 different genders.

Over time, this concession set us on an evolutionary path toward observable gender differences, such as why the mother carries the child and why men attempt to gather money, power and access to mates

Jun 26 2011:
I am sorry, but the question in the title, leaving aside the faulty grammar, is absolutely and completely nonsensical.

1. Not all living forms come in male/female pairs.
2. Why should all species come in "one gender"? How would you define a "gender" without sex separation first?
3. Yes, the proper understanding of evolutionary processes coupled with an analysis of existing and pre-existing (when possible) species, from asexual to semi-sexual, to hermaphrodites, to male/females, to other genetic recombination processes in nature, can help explain the evolution of our particular way of sexual reproduction. The whole answer is valid.

Go to school, study a lot of biology, then try making a question that makes sense.

[S.R. I see that you forgot about this conversation, and I can see why. It must be awful to have discovered that your question, which you surely expected to "stump" those who "believe" evolution, was such a blunder that exposed you as ignorant. Take a lesson my friend: think for yourself, learn actual science, stop trusting creationist material, at the very least verify the creationist claims carefully before deciding to post them. Seems like both the Christian and the Muslim quacks rely on the very same tricks for the unwary, where the unwary includes their clientele, such as you.]

May 18 2011:
True! Sex is only around 700 million years old and considering life arose around 3.800 million years ago, 80% of the history of life took place with no sex! Sexual reproduction and differentiation of gender are something relatively new.

Jun 20 2011:
Micro evolution is a fact no questions about it. The living beings transmit genetic information through generation, adapting and evolving. You can replicate this in a laboratory and you have a scientific true.
The problem is when you use micro evolution as an evidence of macro evolution and use it to explain the origin of life. The macro evolution system can't be replicated in laboratory therefore you can't apply the scientific methods to it.
you can only believe in evolution
Here is a good article about what im trying to say:http://www.exchangedlife.com/Creation/macro-evol.shtml

Comment deleted

Jun 21 2011:
i know that, but the problem is that any observation that can be made is made in the micro evolution level.A fundamental premise of the theory of evolution is that evolution take time so much time that it cant be observed during the life span of a human being . All we have are "evidences" that are hypothesized. those hypothesis are based on the believe that micro evolution (the small genetic adaptation passed through generation) are enough to support the theory of macro evolution, i don't think so .

May 19 2011:
It is still a good question... why and how did sex evolve? My explanation requires a basic understanding of evolution.

Scientists believe they have answers. "The Red Queen" hypothesis seeks to address the question- Why sex? Or in S.R. Ahmadi's case, why pairs?

Matt Ridley's book, "The Red Queen: Sex and the Evolution of Human Nature," is a great read if you are interested. My favorite chapter dealt with what makes humans attractive to the opposite sex, and the more provocative hypothesis that suggest the advanced human brain was a product of sexual selection- the "tricks" the sexes employ to reproduce contribute to escalating intelligence- both to get better at tricking and detecting tricks.

The phrase "Red Queen" derives from a character in Lewis Carroll's novel, "Through the Looking Glass."
The character, The Red Queen, states:
"It takes all the running you can do, to keep in the same place."

Asexual species, such a bacteria and viruses, propagate by making exact copies of their genetic material. The only opportunity they have to adapt to a changing environment is by random mutation. The only reason bacteria are able to be successful is their fast rate of evolution due to the number of generations produce over time. This allows natural selection to work at a much faster pace than organisms with long life spans and lower reproduction rates.

I should also mention many successful bacteria have gene-copying mechanisms that "purposefully" make mistakes in copying genetic material thereby increasing the rate of mutation. This produces genetic variation on which natural selection can act. Also, horizontal gene transfer directly from bacterium to bacterium can convey helpful genes, such as penicillin resistance, to other bacteria.

This is why I say a vast majority of organisms on Earth reproduce asexually- bacteria and viruses comprise a vast majority of organisms on the planet.

Jun 7 2011:
Nature is a minimalist is design, It is required for at least two genders to proliferate successful traits into a majority of the population and even if more genders could do the job, it isn't necessarily required.

May 18 2011:
there is no such thing as "why" in evolution. things just happen, and if they work, they are kept. the closes thing to "why" is

1, how was it possible, what was the path to it, and

2, how was it beneficial, what is the gain.

i personally never encountered any theories about how sexual reproduction was invented. but i know why is it beneficial.

suppose we have a non-sexual reproduction, that is, every individual gives birth to a number of offspring. suppose a beneficial mutation happens in an individual. at the same time, a different beneficial mutation happens in another individual. the two groups start to grow and outcompete the other individuals. and the better of the two will soon outcompete the worse one too. one beneficial mutation is lost.

but if we have sexual reproduction, two offspring of the two ancestors will eventually meet, and have an offspring that has both mutated genes. so with nonsexual reproduction, you have to invent everything yourself. with the sexual reproduction, new genes can be exchanged, and their gains combined.

Jun 27 2011:
There's a book that explains this, it's called "13 things that don't make sense" by Michael Brooks. So I guess none of us will be able to explain it if it's among the most puzzling quests of our time.

It has something to do with evolution I clearly recall, as to why I remember it being the less efficient way to reproduce, hense the non-sense.

Sexual reproduction provides a greater variation of offspring which translate into a great amount of genetic variation in the species, which is an indicator for diversity and survivability of the species. Since our genomes are organized into two copies of alleles, this allows for one allele to mutate and not effect the other. It also creates a "gene pool" from which recessive genes can crusade and perhaps be expressed in later generations as an evolutionary advantage (i.e. desirability of red-haired women). Asexual organisms don't have a "gene pool" or genetic variation because every species is just like the other. Even a "superbug" like MRSA is created and acts differently than regular Staph aureus, it is only a matter of time before horizontal gene transfer results in ALL Staph bugs being MRSA- they will again all be identical.

But there are problems with sex as well. It requires much more energy and effort on the part of the individual organism, but obviously the evolutionary advantages are greater than it's cost. In many (not all) animals, sexual reproduction resulted in male/female, pistil/stamen, plus/minus, etc. The reason for this is a subject I will address in another post (it is the crux of the argument, best fits the question, and I want to address it separately).

The peacock is the poster-child of what sexual evolution can achieve; runaway efforts to attract a mate. The feathers on a peacock show the peahen, "Hey, look, not only and I strong and healthy, but I can maintain this ridiculous tail. You know you love my tail, baby. Your sons will inherit this tail of mine, you know *winkwink."

May 20 2011:
I think the majority of the previous posts answered this sufficiently, but let me summarise:

1. Only a small subset of species are paired by sex.

2. When sexual reproduction arose (c. 700 million years ago from earlier post) it conferred a significant advantage - an additional and efficient way to mix genetic material, not relying largely on random mutation.

3. Evolution works on existing material (mutations aside), and therefore when a highly advantageous 'technique' arises, it generally spreads (intra, and over time, inter-species), versus 'trying' to get a new technique from scratch.

Evolutionary theory (in the scientific sense of 'Theory') answers and accounts for all these 'disputes' / questions raised - well worth reading, should probablly be next the bibles they place in hotel bedsides drawers...

May 20 2011:
Wow, I haven't seen a more misleading or fundamentally flawed post than the second link provided: http://www.randommutation.com/darwinianevolution.htm
The entire argument is disguised as true science, however, it contains a hole you could drive a galaxy through - natural selection works on random mutations, and without seeing them in this light, of course the mechanisms by which they work don't make sense.
Random mutations provide the baseline variation in genetic material, and natural selection works on those few that provide some benefit. The sentence provided 'the quick brown fox jumped over the lazy dog' could certainly be changed to a different and meaningful sentence by random mutation if an equivalent of natural selection were introduced - i.e. only those changes that were not detrimental to the understanding of the sentence were kept, and those changes that 'improved' the sentence were selected for.
Must say, the elementary attempts at obfuscation and discreditation of evolution, largely by religious entities, would be humerous if so many weren't fooled...

Help me out here. Surely if the sentence is accurate as it is then any mutation is going to be detrimental. There is no reason for natural selection to favour a change unless it was a change which improved the sentence. The chances of that are surely minimal; or perhaps you can direct me to an example. Fruit Flies comes to mind. They have been mutating those for thousands of generations without success.
I stumbled across this link, which claims that the dna doesn't control the 'body plan', so mutating the dna can have no effect whatsoever on the overall plan of the creature. This; if true; would make the whole thing academic.

(Hello man!) This looks insulting because we have gone through it already.

The reason why "the propaganda machine" has been silent on the issue is that there is no propaganda machine. Evolution is just science. For propaganda, go to ... ups too late, you already went to creationists web sites.

As for science, there is no silence whatsoever, and I am surprised that you would start that way. If science is silent about sexual reproduction and its evolution where do your propagandists take those misquotes from?

Anyway, sexual reproduction starts with recombination, not with genders. Genders come much later. Sometimes in very simplified forms (incompatibility for mating between organisms unless they carry a complementary mating gene), sometimes completely absent (anything goes in terms of mating cells). There are examples of almost every stage imaginable in today's living forms Peter. We don't even have space for some [educated] speculation. Maybe you can see that there is no need for evolution to "know" the advantages before evolving sex. It is enough for two cells to be able to mix their genetic material to attain the advantages of recombination.

As for mutations, it is a failed hypothesis that most mutations would be harmful. Most are from neutral to semi-neutral. This has been demonstrated both in the lab and confirmed in the analyses of living organisms. I told you this already.

Good to hear from you again. Hey if it wasn't for gullible Christians TED would be a dull place.

I like the quacks, they make sense to me. I like the debates, iron sharpens iron. I don't have your education or intellect; but when you look around at our bankers & politicians maybe what the world needs is a bit more 'common sense'; & I have some of that. We all have our part to play.
If you want to make your mark, you really have to take the quacks on. Debate them on the science; name calling is a bit beneath you.

Nice to see you around. I agree that the site would be dull without the fundies. :) But at the same time it is sad that it would be so. :(

As for common sense. I erased a comment telling you about PP's video. But a point I should still make is this: if "evolutionists" don't want to "talk about it," and sex is something they really don't want to discuss in public, why did PP cite an "evolutionist" at the beginning of that video? Where did he take all those other misquotes about the "problem" of the evolution of sex from? Why is that first quote from a book on the evolution of sex itself, from an "evolutionist," if they are so afraid of the "issue"? Do you think an evolutionist would not cite any research when writing an entire book on the subject? So, PP's video is merely rhetorical.

From the above, there is no debate to be held on the science. Creationists have no idea (or have a very twisted idea), and it would take forever to dismantle the threads of misinformation they are able to put together. It is as if I told you to debate me on biblical meaning, but all you saw from me were misquotations that have nothing to do with the bible, except in names of characters, and, based on such false assumptions I asked you something on top of that. If you started by telling me that my question is wrong from the beginning, I answer with another series of misquotations, while those on "my side" applaud my tricks as if they meant truth. Would you take me seriously for a debate? Suppose I asked you "have you stopped beating your wife? Yes or no!" You babble because the very foundation of the question is wrong, yet I see your surprised stare and use it as "proof" that you were stumped by the truth you deny to acknowledge. Well, that's exactly the kinds of rhetorical devices that creationist quacks build.

May 18 2011:
Not ALL species come into male & female pairs. Beside the hermaphroditic species in plants and in unicellular organisms many invertebrates such as snails, slugs, most molluscs and worms (e.g. Tapeworm) in addition to some lizards are bisexual animals where the individual/organism have both male and female reproductive organs (e.g. ovotestis).

We also have species like some African frogs that can change their gender.

If species had only one gender then without any other means of reproduction that species would die off in one generation.

Having pair of species is a good way to maintain a good gene pool allowing for strong individuals in that pool to pass on their gene to more offspring than other individuals, thus improving the change of survival of the species overall.

May 17 2011:
Many animal and other species have a male-female reproduction system because this is what evolved early on in the tree of life. It is s synapomorphy (meaning a shared trait) of all the species that have evolved after the first species that had male and female sexual reproduction. Of course, some species we see today have diverged from this ancestral character state, such as the ones mention by Lynn.